<?php
/**
 * Created by PhpStorm.
 * User: XD
 * Date: 2017/9/4
 * Time: 14:45
 */
 function a($txt){
     b("Glenn");
 }
 function b($txt){
     c("Cleveland");
 }
 function c($txt){
     var_dump(debug_backtrace());
 }
 a("peter");